Reply to post: Yep

Yep

Yep, since the 1980's the metre has been defined as the distance that light travels in a vacuum over 1/299792458th of a second. This makes it easier to derive your own local metre without having to traipse over to Paris to check your metre rule against their 'standard' metre rule. A side effect of this is that the speed of light is fixed at exactly 299792458m/s.